From: Akihiko Odaki <akihiko.odaki@daynix.com>
To: Paolo Bonzini <pbonzini@redhat.com>, Stefan Weil <sw@weilnetz.de>,
Peter Xu <peterx@redhat.com>, Fabiano Rosas <farosas@suse.de>,
Hailiang Zhang <zhanghailiang@xfusion.com>
Cc: "Phil Dennis-Jordan" <phil@philjordan.eu>,
qemu-devel@nongnu.org, devel@daynix.com,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Daniel P. Berrangé" <berrange@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@linaro.org>,
"Akihiko Odaki" <akihiko.odaki@daynix.com>
Subject: [PATCH v2 5/9] qemu-thread: Use futex if available for QemuLockCnt
Date: Sat, 10 May 2025 17:51:50 +0900 [thread overview]
Message-ID: <20250510-event-v2-5-7953177ce1b8@daynix.com> (raw)
In-Reply-To: <20250510-event-v2-0-7953177ce1b8@daynix.com>
This unlocks the futex-based implementation of QemuLockCnt to Windows.
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
include/qemu/lockcnt.h | 2 +-
util/lockcnt.c | 7 ++++---
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/include/qemu/lockcnt.h b/include/qemu/lockcnt.h
index f4b62a3f7011..5a2800e3f182 100644
--- a/include/qemu/lockcnt.h
+++ b/include/qemu/lockcnt.h
@@ -17,7 +17,7 @@
typedef struct QemuLockCnt QemuLockCnt;
struct QemuLockCnt {
-#ifndef CONFIG_LINUX
+#ifndef HAVE_FUTEX
QemuMutex mutex;
#endif
unsigned count;
diff --git a/util/lockcnt.c b/util/lockcnt.c
index ca27d8e61a5c..92c9f8ceca88 100644
--- a/util/lockcnt.c
+++ b/util/lockcnt.c
@@ -12,10 +12,11 @@
#include "qemu/atomic.h"
#include "trace.h"
-#ifdef CONFIG_LINUX
-#include "qemu/futex.h"
+#ifdef HAVE_FUTEX
-/* On Linux, bits 0-1 are a futex-based lock, bits 2-31 are the counter.
+/*
+ * When futex is available, bits 0-1 are a futex-based lock, bits 2-31 are the
+ * counter.
* For the mutex algorithm see Ulrich Drepper's "Futexes Are Tricky" (ok,
* this is not the most relaxing citation I could make...). It is similar
* to mutex2 in the paper.
--
2.49.0
next prev parent reply other threads:[~2025-05-10 8:53 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-10 8:51 [PATCH v2 0/9] Improve futex usage Akihiko Odaki
2025-05-10 8:51 ` [PATCH v2 1/9] futex: Check value after qemu_futex_wait() Akihiko Odaki
2025-05-10 8:51 ` [PATCH v2 2/9] futex: Support Windows Akihiko Odaki
2025-05-10 8:51 ` [PATCH v2 3/9] qemu-thread: Avoid futex abstraction for non-Linux Akihiko Odaki
2025-05-10 15:02 ` Paolo Bonzini
2025-05-11 4:41 ` Akihiko Odaki
2025-05-10 8:51 ` [PATCH v2 4/9] qemu-thread: Use futex for QemuEvent on Windows Akihiko Odaki
2025-05-10 8:51 ` Akihiko Odaki [this message]
2025-05-10 8:51 ` [PATCH v2 6/9] migration: Replace QemuSemaphore with QemuEvent Akihiko Odaki
2025-05-10 8:51 ` [PATCH v2 7/9] migration/colo: " Akihiko Odaki
2025-05-10 8:51 ` [PATCH v2 8/9] migration/postcopy: " Akihiko Odaki
2025-05-10 8:51 ` [PATCH v2 9/9] hw/display/apple-gfx: " Akihiko Odaki
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